Introduction

During the past few years there has been considerable interest in the way in which the composition of the acid resistant organic content of sedimentary rocks can be used to aid the interpretation of depositional environments. However, much of the published work has not involved fully comprehensive analyses. There has been a tendency to concentrate either on the distribution of palynomorphs at the expense of less well characterized phytoclasts, or on the shape and composition of the particulate detritus recovered, with scant attention being paid to the environmental implications of the presence of individual species of microfossils. As a result, much information of potential value to the aims of palynofacies analysis has been lost. In addition, comparatively little use has been made of numerical methods in analyzing and interpreting the data. Multivariate methods, which reduce the dimensionality of the data, can bring the most important trends to the fore and provide a quantitative basis for assessing these in the light of lithology and depositional environment. They also provide a graphical means of presenting the results much more effectively than through written descriptions alone.

In this chapter we review a variety of approaches that may be taken to analyze palynofacies and depositional environments, concentrating on the use of quantitative and multivariate methods. In order to demonstrate the usefulness of these techniques, we re-analyze a number of previously published sets of palynological and palynofacies data with principal components and cluster analyses, using the computer program MVSP (Kovach, 1990). We also discuss approaches other authors have taken in applying numerical methods to palynofacies studies in order to demonstrate the range of techniques available.